Fluid buffer device for elevators.



I P. G. PURLOW. H4111) BUFFER DEVICE FOR ELEVATORS.

APPLICATION FILED FEB. 4, 1911.

' Patented June 10, 1913.-

( g mme Mo;

K 95x3 A) Sign 1e Unirn stains Parana rice.

FLOYD C. IFURLOW', OF MONTCLAIR, NEW JERSEY,

ASSIG-NOR '110 OTIS ELEVATOR. COM- PANY, F JERSEY CITY, NEW JERSEY, ACORPORATION OF NEW JERSEY.

., FL UID BUFFER DEVICE FOR ELEVATORS.

Specification of Letters Patent.

Patented June 10,1913;

Original application filed October 9, 1907, Serial No. 396,553, Dividedand this application filed February Serial No. 606,468.

To all whom it may concern:

Be it known that I, Fnovn C. Funnow, a citizen of the United States,residing at Montclair, in the county of Essex and State of New Jersey,have invented a new and useful Improvement. in Fluid Butter Devices forElevators, of which the following is a specification.

My invention relates to safety buffers for elevators, and thisapplication is a. division of my co-pending application, Serial No.896,553. filed October 9 1907, for fluid dashpot buffer device.

The invention consists of a device for gradually retarding an elevatorcar or other moving element independently of its operating apparatus, soas to bring the parts gradually to rest without shock or jar.

The invention also comprises means for resetting or returning the bufferdevice to its initial position, when the same is released by the movingpart of the elevator which is arranged to engage the butter device.

The exactnature of the invention and the specific objects sought-to beattained will appear hereinafter in connection with the detaileddescription of the invention and the appended claims.

In the accompanying drawings, Figure 1 represents an elevator systemillustrating an application of my invention: Fig. 2 is a verticalsectional elevation of my improved buffer device including the resettingmeans.

In general my invention comprises a butter device or shockabsorber'adapted to overcome the inertia of a moving body in an elevatorin gradually stopping the same.

In the drawings I have shown the butter device in position to be engagedby the elevator car as it approaches its lower limit oftravel, althoughobviously it might be placed in the path of the counterweight or othermoving part which it is desired to stop gradually, where such part is inan ele-' vator system or other analogous apparatus.

In Fig. 1 two cushioning devices of the form shown in detail in Fig. 2are shown at the bottom of the elevator well in position to be engagedby the elevator car as the same approaches'its lower limit of travel.

and by the combined retarding action of springs and a varying fluidpressure, bring the 'car to a complete stop gradually and inweight ofthe car and the 'car. near the dependently of manual controllers,although the car may be descending at a high rate'of speed. I

Fig. 1 illustrates a typical hydraulic elevator of the well knownplunger type, the elevator car 1 traveling along the usual guide rails(not shown). To the bottom of the car is securely attached the plunger 2uhich is arranged to move up and down freely in the main cylinder 18.The latter supplied with fluid under pressure through the to-and-frompipe 16 from the pressure supply pipe 14 through the change valve 17. 15designates the discharge or exhaust pipe. The operation of the changevalve 17 is controlled by means of a hand lever 10 in the carcoiiperating with the standing ropes 9, the sheave 11, the pinion 12 andthe rack bar 13 in the well known manner. The standing ropes 9 arefastened at 8 to the overhead beam 6. The cable 4 is attached to theupper side ofthe car and extends upwardly over the sheave 5, mounted onthe overhead beam 6 to the counterbalance weight 7. The counterweightpartially balances the combined weight of the car and plunger. Thecylinder 18 is closed at its lower end by a head 19 and when the caroperating lever 10 is moved in one direction or the other, the changevalve 17 will be operated to open or closed position to allow the supplypressure to act on the plunger to lift the car or so as to cause theunbalanced plunger andload to force the fluid out of the cylinderthrough the exhaust pipe 15.

Although in some instances only one buffer device would be suflicient,it would be preferable in stopping an elevator car to employ a pluralityof them. In this instance I have shown two buffer devices 20 in Fig. 1at the lower limit of travel of the elevator car, and so placed inrespect thereto that each will be engaged by the bottom of lower limitof the cars travel.

Referring now to Fig. 2 which shows the invention in detail, a heavycompression spring 21 is loosely mounted in a; short tube or invertedcap 22 secured to the top of a tubular piston rod 25. The spring 21 issurmounted by a rubber helps to deaden the blow cushion 23 whichof theelevator car or other moving part when it strikes the lltt butter. Thelower end of the piston rod is screwthreaded to receive a collar 26 boltgyd on to a piston 27. The piston rod is provided with a series ofperforations 28 near its lower end. A tubular casing 29 isscrewthreaded. into a support or standard 30 which is provided withholes 31 for bolts or other fastening means to securely hold the butterdevice in proper position.

The bottom of the casing '29 is provided with a recess 32 which isscrewthreaded to receive the lower screwthreaded end of a tube 33.Within the tube 33 is a hollow rod 34 extending from the bottom of thetube 33 up through acentral opening in the piston 27 and into the pistonrod 25. Surrounding the rod 234i. is a coil spring 35 which rests on thetube and terms a resilient stop for the piston 27 and parts carriedthereby. The hollow rod 34 provided with a series oi. graduated openings36 extending fromnear the top of the rod to a point a short distanceabove the top of the tube These openings are of gradually diminishingdiameters from the top one which is large enough to oilr-cbut little orpractically no resistance to the flow of oil therct-hrough. to thelowest openii'lg which will allow the oil to pass only very slowly. Acoil spring; 37 yieldingly holds the piston 27 in its upper position andreturns it to such position after the butter device has operated. Boltedto the upper end of the casingQt-l is a hollow cap 38 which storms aliquid receptacle. This cap surrounds thedlollow piston rod 25 and isprovided with a stutfinp; box 39 to guide the tube 25 and prevent escapeof the liquid. Openings 38' in the cap 38 permit the escape of airdisplaced by the piston rod 25 as it descends. and including thecylinder 29 and cap 38 is filled with oil or other liquid. The hollowrod 3'4 is therefore also filled. Any suitable'lirpiid such as wal'er'oroil may be used. lVhile itmay be possible to use water or other similarvliquid or even to have the cylinder contain only air, I prefer to employoil since it prevents rusting" or corrosion, does not evaporateappreciably and at the same time lubricates all themoving parts.Furthermore. there is no possibility of the oil. freezing and therebyrendering the device inoperative.

The operation of the buffer device is substantially as follows: V Vhenthe elevator car or other moving part which it is desired to bring to agradual stop and which maybe traveling at a high rate of speed, strikesthe butter, the spring 21 is compressed and the piston rod 25 and'piston27 start gradually downward. The spring 21 acts as a cushion for thepiston rod and piston and thus prevents them from receiving a sudden andviolent blow and also permits them to-be started gradually. The rubbercushionQS The receptacle. taken as a whole also serves to further deadenthe blow. the piston 27 commences its downward'move ment, the oilbeneath it is forced into the hollow rod 34, the oil in the rod beingforced oullvard through the top of the rod and the openings 36 which areabove the piston, and through the openings 28 into the space above thepiston.' As the area of the openings both above and below the piston islarge;

very little resistance is offered to the flow of the oil during theinitial movement of the piston, and the latter is enabled to accelerratevery rapidly. T hat is. it quickly takes up the running speed of thecar. the back pressure due to the inertia of the piston and. piston rodin starting being absorbed by the spring 21. The: circulation of the oilas above noted continues as the piston d escends. the restriction to theflow oi. oil gradually becoming greater as the number and size of theopeningswiG below the pistoii diminish. W hen the piston has covered thelast opening 36, it will be brought to rest. owing to the incompressiblenature of the oil. unless there is leakage between the piston 27 and thecylinder 29. or between the piston and the rod 34, in which case it maymo re far enough to compress the spring 35. and will then be brought toan absolute stop. The spring will act as a buli'er to stop the ca rwithout any in case it is not brought to a com plete stop by theretarding effect of the oil.

.Vhile I have described my invention in connection with an elevatorsystem. there are doubtless other uses to which my inven tion could beput to great advantage with. outiuvention. Various changes in thedetails and arrangement of parts might also be made by those skilled inthe art without departing from the spirit. and, scope oi the invention.I desire therefore not to be limited to the particular construction andan rangement of parts disclosed.

lVhat I claim as new and desire to secure by Letters Patent of theUnited States is 1. Tu an elevator buffer. the cmubination ot acylinder. a piston movable therein. a hollow piston rod. and a hollowmember stationanv with respect to the cylinder. extending through thepiston and into the piston rod and formed to permit a gradually restricted' passage of a fluid through said piston rod from one side ofthe piston to the other during the movement of the piston.

2. In an elevator buller. the combination of a cylinder. :1. pistonmovable therein and. provided with an opening. and a hollow membermovable relative to the piston through said opening and provided with anopening oropenings in position to gradually restrict the passage of aliquid from one side of the piston to the other.

3. In an elevator buffer, the combination of a cylinder, a-pistontherein provided with an. opening, and a hollow rod within the cyl- ALSinder and extending through the'sa-id opening, said rod being formedwith a series of lateral openings arranged to successively oppose thepiston.

4. In an elevator buffer, the combination of a cylindrical casing, acylindrical hollow rod within the casing and formed with a series ofgraduated lateral openings, a piston formed with an opening throughwhich the said hollow rod extends, and a pistonrod.

5. In an elevatorbutfer, the combination of a receptacle, a pistonmovable therein, a hollow piston rod connected to the piston, and astationary hollow'rod in the'receptiacle and extending through thepiston into the piston rod, said stationary rod being formed with aseries of lateral openings.

6. The combination of a cylindrical receptacle, a piston movable thereinand having a substantially liquid tight fit in the receptacle, and ahollow cylindrical rod within the receptacle and slidable through anopening in the piston which forms 'during such movement a substantiallyliquid tight joint with the rod, said hollow rod being provided with anopening or openings in' position to gradually restrict the flow of aliquid from one side of the piston to the other as itmoves in thereceptacle.

7. In an elevator bufl'er, the combination of a cylindrical receptacle,a piston formed with an opening, a hollow piston rod, and

a hollow stationary member located in the receptacle and extendingthrough said opening into the hollow piston rod, and a series pf lateralopenings in the said hollow mem- J81.

8. In an elevator butter, the combination ofa vertical stationaryreceptacle, a liquid therein, a piston movable vertically in thereceptacle and formed 'with an opening therethrough, a hollow stationarymember extending through said opening and provided with a lateralopening or openings of position and size to effect a gradual throtgigtling of the liquid as the piston moves downward, and means carried bythe piston to be engaged by a moving part of the elevator.

9. In an elevator buffer, the combination of a receptacle, a piston andhollow piston rod movable therein, a liquid within the receptacle, a capor cover for the receptacle formed with an opening through which thepiston rod extends; a hollow cylinder stationary within the receptacleand extending through the piston into the piston rod, said cylinder andpiston rod being formed with lateral openings in position to permit atransfer of the liquid-from the lower side to the upper side of thepiston and effect a gradual throttling of the liquid as the pistondescends.

10. In a butler device, the combination of a cylinder, a piston movabletherein, a liquid in the cylinder, means for gradually restricting theflow of liquid as the piston is moved, and resilient means for retardingthe piston brought into operation after the operation of saidrestricting means.

11. In an elevator buifer, the combination of a receptacle liquidtherein, a member movable through the liquid, means for graduallyrestricting the transfer of liquid from one side to the other of saidmember during such movement, and a resilient device to bring the saidmovable member to a ,full

stop after the operation of said means.

12. In an elevator bufier, the combination of a receptacle, a pistonmovable therein, a hollow member extending through an opening in thepiston and formed with openings to variably retard the movement of thepiston, and a spring or springs to reset the buffer.

In testimony whereof, I have signed my name to this specification in thepresence of two subscribing witnesses. Y

FLOYD C. FURLOW.

Witnesses:

ELEANOR W. CALLAIIAN, W. H. BRADY.

